US Air Force B-2 bombers and drones have attacked a pair of Islamic State military camps in Libya, seeking to eliminate extremists who had escaped the former IS stronghold of Sirte.
A United States defence official said the camps were located about 45 kilometres south-west of the central coastal city of Sirte.
The official was not authorised to speak in advance of an expected Pentagon announcement and confirmed the strikes on condition of anonymity.
The strikes were authorised by President Barack Obama, marking perhaps the final use of military force by a wartime president who intervened in Libya in 2011 as part of a coalition that ultimately toppled dictator Moammar Gadhafi.
The Pentagon believes no civilians were killed in the strikes, the official said, while "several dozen" IS militants are thought to have been killed.
The defence official said the latest strikes were aimed at hitting Islamic State militants who left Sirte after US strikes largely eliminated the group's presence in that coastal city in December.
